diff options
Diffstat (limited to 'arch/i386/boot/video.c')
| -rw-r--r-- | arch/i386/boot/video.c | 456 |
1 files changed, 456 insertions, 0 deletions
diff --git a/arch/i386/boot/video.c b/arch/i386/boot/video.c new file mode 100644 index 00000000000..3bb3573cd6a --- /dev/null +++ b/arch/i386/boot/video.c @@ -0,0 +1,456 @@ +/* -*- linux-c -*- ------------------------------------------------------- * + * + * Copyright (C) 1991, 1992 Linus Torvalds + * Copyright 2007 rPath, Inc. - All Rights Reserved + * + * This file is part of the Linux kernel, and is made available under + * the terms of the GNU General Public License version 2. + * + * ----------------------------------------------------------------------- */ + +/* + * arch/i386/boot/video.c + * + * Select video mode + */ + +#include "boot.h" +#include "video.h" +#include "vesa.h" + +/* + * Mode list variables + */ +static struct card_info cards[]; /* List of cards to probe for */ + +/* + * Common variables + */ +int adapter; /* 0=CGA/MDA/HGC, 1=EGA, 2=VGA+ */ +u16 video_segment; +int force_x, force_y; /* Don't query the BIOS for cols/rows */ + +int do_restore = 0; /* Screen contents changed during mode flip */ +int graphic_mode; /* Graphic mode with linear frame buffer */ + +static void store_cursor_position(void) +{ + u16 curpos; + u16 ax, bx; + + ax = 0x0300; + bx = 0; + asm(INT10 + : "=d" (curpos), "+a" (ax), "+b" (bx) + : : "ecx", "esi", "edi"); + + boot_params.screen_info.orig_x = curpos; + boot_params.screen_info.orig_y = curpos >> 8; +} + +static void store_video_mode(void) +{ + u16 ax, page; + + /* N.B.: the saving of the video page here is a bit silly, + since we pretty much assume page 0 everywhere. */ + ax = 0x0f00; + asm(INT10 + : "+a" (ax), "=b" (page) + : : "ecx", "edx", "esi", "edi"); + + /* Not all BIOSes are clean with respect to the top bit */ + boot_params.screen_info.orig_video_mode = ax & 0x7f; + boot_params.screen_info.orig_video_page = page; +} + +/* + * Store the video mode parameters for later usage by the kernel. + * This is done by asking the BIOS except for the rows/columns + * parameters in the default 80x25 mode -- these are set directly, + * because some very obscure BIOSes supply insane values. + */ +static void store_mode_params(void) +{ + u16 font_size; + int x, y; + + /* For graphics mode, it is up to the mode-setting driver + (currently only video-vesa.c) to store the parameters */ + if (graphic_mode) + return; + + store_cursor_position(); + store_video_mode(); + + if (boot_params.screen_info.orig_video_mode == 0x07) { + /* MDA, HGC, or VGA in monochrome mode */ + video_segment = 0xb000; + } else { + /* CGA, EGA, VGA and so forth */ + video_segment = 0xb800; + } + + set_fs(0); + font_size = rdfs16(0x485); /* Font size, BIOS area */ + boot_params.screen_info.orig_video_points = font_size; + + x = rdfs16(0x44a); + y = (adapter == ADAPTER_CGA) ? 25 : rdfs8(0x484)+1; + + if (force_x) + x = force_x; + if (force_y) + y = force_y; + + boot_params.screen_info.orig_video_cols = x; + boot_params.screen_info.orig_video_lines = y; +} + +/* Probe the video drivers and have them generate their mode lists. */ +static void probe_cards(int unsafe) +{ + struct card_info *card; + static u8 probed[2]; + + if (probed[unsafe]) + return; + + probed[unsafe] = 1; + + for (card = video_cards; card < video_cards_end; card++) { + if (card->unsafe == unsafe) { + if (card->probe) + card->nmodes = card->probe(); + else + card->nmodes = 0; + } + } +} + +/* Test if a mode is defined */ +int mode_defined(u16 mode) +{ + struct card_info *card; + struct mode_info *mi; + int i; + + for (card = video_cards; card < video_cards_end; card++) { + mi = card->modes; + for (i = 0; i < card->nmodes; i++, mi++) { + if (mi->mode == mode) + return 1; + } + } + + return 0; +} + +/* Set mode (without recalc) */ +static int raw_set_mode(u16 mode) +{ + int nmode, i; + struct card_info *card; + struct mode_info *mi; + + /* Drop the recalc bit if set */ + mode &= ~VIDEO_RECALC; + + /* Scan for mode based on fixed ID, position, or resolution */ + nmode = 0; + for (card = video_cards; card < video_cards_end; card++) { + mi = card->modes; + for (i = 0; i < card->nmodes; i++, mi++) { + int visible = mi->x || mi->y; + + if ((mode == nmode && visible) || + mode == mi->mode || + mode == (mi->y << 8)+mi->x) + return card->set_mode(mi); + + if (visible) + nmode++; + } + } + + /* Nothing found? Is it an "exceptional" (unprobed) mode? */ + for (card = video_cards; card < video_cards_end; card++) { + if (mode >= card->xmode_first && + mode < card->xmode_first+card->xmode_n) { + struct mode_info mix; + mix.mode = mode; + mix.x = mix.y = 0; + return card->set_mode(&mix); + } + } + + /* Otherwise, failure... */ + return -1; +} + +/* + * Recalculate the vertical video cutoff (hack!) + */ +static void vga_recalc_vertical(void) +{ + unsigned int font_size, rows; + u16 crtc; + u8 ov; + + set_fs(0); + font_size = rdfs8(0x485); /* BIOS: font size (pixels) */ + rows = force_y ? force_y : rdfs8(0x484)+1; /* Text rows */ + + rows *= font_size; /* Visible scan lines */ + rows--; /* ... minus one */ + + crtc = vga_crtc(); + + out_idx((u8)rows, crtc, 0x12); /* Lower height register */ + ov = in_idx(crtc, 0x07); /* Overflow register */ + ov &= 0xbd; + ov |= (rows >> (8-1)) & 0x02; + ov |= (rows >> (9-6)) & 0x40; + out_idx(ov, crtc, 0x07); +} + +/* Set mode (with recalc if specified) */ +static int set_mode(u16 mode) +{ + int rv; + + /* Very special mode numbers... */ + if (mode == VIDEO_CURRENT_MODE) + return 0; /* Nothing to do... */ + else if (mode == NORMAL_VGA) + mode = VIDEO_80x25; + else if (mode == EXTENDED_VGA) + mode = VIDEO_8POINT; + + rv = raw_set_mode(mode); + if (rv) + return rv; + + if (mode & VIDEO_RECALC) + vga_recalc_vertical(); + + return 0; +} + +static unsigned int get_entry(void) +{ + char entry_buf[4]; + int i, len = 0; + int key; + unsigned int v; + + do { + key = getchar(); + + if (key == '\b') { + if (len > 0) { + puts("\b \b"); + len--; + } + } else if ((key >= '0' && key <= '9') || + (key >= 'A' && key <= 'Z') || + (key >= 'a' && key <= 'z')) { + if (len < sizeof entry_buf) { + entry_buf[len++] = key; + putchar(key); + } + } + } while (key != '\r'); + putchar('\n'); + + if (len == 0) + return VIDEO_CURRENT_MODE; /* Default */ + + v = 0; + for (i = 0; i < len; i++) { + v <<= 4; + key = entry_buf[i] | 0x20; + v += (key > '9') ? key-'a'+10 : key-'0'; + } + + return v; +} + +static void display_menu(void) +{ + struct card_info *card; + struct mode_info *mi; + char ch; + int i; + + puts("Mode: COLSxROWS:\n"); + + ch = '0'; + for (card = video_cards; card < video_cards_end; card++) { + mi = card->modes; + for (i = 0; i < card->nmodes; i++, mi++) { + int visible = mi->x && mi->y; + u16 mode_id = mi->mode ? mi->mode : + (mi->y << 8)+mi->x; + + if (!visible) + continue; /* Hidden mode */ + + printf("%c %04X %3dx%-3d %s\n", + ch, mode_id, mi->x, mi->y, card->card_name); + + if (ch == '9') + ch = 'a'; + else if (ch == 'z' || ch == ' ') + ch = ' '; /* Out of keys... */ + else + ch++; + } + } +} + +#define H(x) ((x)-'a'+10) +#define SCAN ((H('s')<<12)+(H('c')<<8)+(H('a')<<4)+H('n')) + +static unsigned int mode_menu(void) +{ + int key; + unsigned int sel; + + puts("Press <ENTER> to see video modes available, " + "<SPACE> to continue, or wait 30 sec\n"); + + kbd_flush(); + while (1) { + key = getchar_timeout(); + if (key == ' ' || key == 0) + return VIDEO_CURRENT_MODE; /* Default */ + if (key == '\r') + break; + putchar('\a'); /* Beep! */ + } + + + for (;;) { + display_menu(); + + puts("Enter a video mode or \"scan\" to scan for " + "additional modes: "); + sel = get_entry(); + if (sel != SCAN) + return sel; + + probe_cards(1); + } +} + +#ifdef CONFIG_VIDEO_RETAIN +/* Save screen content to the heap */ +struct saved_screen { + int x, y; + int curx, cury; + u16 *data; +} saved; + +static void save_screen(void) +{ + /* Should be called after store_mode_params() */ + saved.x = boot_params.screen_info.orig_video_cols; + saved.y = boot_params.screen_info.orig_video_lines; + saved.curx = boot_params.screen_info.orig_x; + saved.cury = boot_params.screen_info.orig_y; + + if (heap_free() < saved.x*saved.y*sizeof(u16)+512) + return; /* Not enough heap to save the screen */ + + saved.data = GET_HEAP(u16, saved.x*saved.y); + + set_fs(video_segment); + copy_from_fs(saved.data, 0, saved.x*saved.y*sizeof(u16)); +} + +static void restore_screen(void) +{ + /* Should be called after store_mode_params() */ + int xs = boot_params.screen_info.orig_video_cols; + int ys = boot_params.screen_info.orig_video_lines; + int y; + addr_t dst = 0; + u16 *src = saved.data; + u16 ax, bx, dx; + + if (graphic_mode) + return; /* Can't restore onto a graphic mode */ + + if (!src) + return; /* No saved screen contents */ + + /* Restore screen contents */ + + set_fs(video_segment); + for (y = 0; y < ys; y++) { + int npad; + + if (y < saved.y) { + int copy = (xs < saved.x) ? xs : saved.x; + copy_to_fs(dst, src, copy*sizeof(u16)); + dst += copy*sizeof(u16); + src += saved.x; + npad = (xs < saved.x) ? 0 : xs-saved.x; + } else { + npad = xs; + } + + /* Writes "npad" blank characters to + video_segment:dst and advances dst */ + asm volatile("pushw %%es ; " + "movw %2,%%es ; " + "shrw %%cx ; " + "jnc 1f ; " + "stosw \n\t" + "1: rep;stosl ; " + "popw %%es" + : "+D" (dst), "+c" (npad) + : "bdSm" (video_segment), + "a" (0x07200720)); + } + + /* Restore cursor position */ + ax = 0x0200; /* Set cursor position */ + bx = 0; /* Page number (<< 8) */ + dx = (saved.cury << 8)+saved.curx; + asm volatile(INT10 + : "+a" (ax), "+b" (bx), "+d" (dx) + : : "ecx", "esi", "edi"); +} +#else +#define save_screen() ((void)0) +#define restore_screen() ((void)0) +#endif + +void set_video(void) +{ + u16 mode = boot_params.hdr.vid_mode; + + RESET_HEAP(); + + store_mode_params(); + save_screen(); + probe_cards(0); + + for (;;) { + if (mode == ASK_VGA) + mode = mode_menu(); + + if (!set_mode(mode)) + break; + + printf("Undefined video mode number: %x\n", mode); + mode = ASK_VGA; + } + vesa_store_edid(); + store_mode_params(); + + if (do_restore) + restore_screen(); +} |